Hi, its important to consider that the large contact area of the wide rear tyres causes more road noise and the tyres are much closer to the driver/cockpit area than most cars so you will notice road noise more. However, apart from using extra layer of carpet etc in the boot (or trunk) you will notice the vast empty spaces inside the rear wings which is accessed through the rear light bulb access panels. This spaces resonates road noise, and can be filled out with foam quite easily to reduce this.

Cheers,
Steve